Setting up a new server - ntp

Super brief notes on configuring NTP

Make sure ntp is installed
rpm -qa | grep ntp
yum install ntp

Edit /etc/ntp.conf
Add stratum servers from www.ntp.org - check the server pool for your locale.

I added these:
server 0.north-america.pool.ntp.org
server 1.north-america.pool.ntp.org
server 2.north-america.pool.ntp.org
server 3.north-america.pool.ntp.org

And this to restrict access from those servers:
restrict 0.north-america.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery
restrict 1.north-america.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery
restrict 2.north-america.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery
restrict 3.north-america.pool.ntp.org mask 255.255.255.255 nomodify notrap noquery

And permit any host in my private network to get time from my server:
restrict 10.1.1.0 mask 255.255.255.0 nomodify notrap

check if ntpd is currently running:
ps -ef | grep ntp
no dice, so configure it to start at boot

chkconfig --list ntpd
ntpd 0:off 1:off 2:off 3:off 4:off 5:off 6:off

Check to see if the server time is reasonably close to ntp time (within 2 minutes), if not run:
ntpdate pool.ntp.org
to synchronize.

Run:
chkconfig ntpd on
service start ntpd

Check for log messages in /var/log/messages and check the time on the server to see if it's accurate. Also check status with:
[root@server etc]# ntpq -pn
remote refid st t when poll reach delay offset jitter
==============================================================================
64.73.32.134 64.73.0.9 2 u 30 64 1 72.596 4.418 0.001
66.250.45.2 209.51.161.238 2 u 29 64 1 92.327 -8.728 0.001
66.36.239.127 129.6.15.29 2 u 28 64 1 86.409 1.150 0.001
82.165.184.7 74.208.4.166 3 u 27 64 1 88.581 -7.514 0.001
127.127.1.0 .LOCL. 10 l 26 64 1 0.000 0.000 0.001

Tip of the keyboard to:
ntp.org
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